Gas burner



K- B. ANDERSON GAS BURNER,

Filed July 22, 1929 Nn TN April 5, 1932.

Patented Apr. 5, 1932 UNITED STATES PATENT OFFICE GAS BURNER applicati med my as,

This invention has reference to gas burners, and particularly burners of the type adapted for use in tiring furnaces, boilers and the like. In some of its aspects, the inV t vention embodies certain general characteristics similar to the form of burner described in the Patent No. 1,707,451, issued April 2,

i929, to John V.- Thomas and Ben D. Balthis,

p but is directed more particularly to improved t features of design and adjustment which give to burners of this type materially increased eiciency both in minimizing fuel consumption and in enabling the desired and proper combustion of the fuel. lit lin the operation of burners for industrial installations, difficulty is commonly experisneed in controlling the llame whereby complete combustion of the fuel may be had and at the same time preventing the llame from sweeping across the metal heating surfaces, iter instance in stills and boilers. The deleterious eects of permitting the flame to come i in contact with the metal heating Walls are well known to those familiar with the art. llt is a purpose of the invention therefore to provide a burner in which the fuel and air are inixed and proportioned in Aa manner such as to burn with a comparatively short and intense flame to the end that more even heat distribution is had in the heating zone, and the flame is prevented from contacting with the metallic heating surfaces, lthe transfer of heat occurring mainly b radiation and convection through the medium of the completely burned combustion gases.

'llhe present type of burner may be characterized generally as comprising a fuel and air ruining tube arranged in the air intake passage to the combustion zone, fuel being delivered to the mixing tube by way of a preferably specially designed nozzle, described more fully hereinafter. A certain proportion, which may be termed the priinary air, of the total air required for thorough combustion of the fuel, is drawn into the mixing tube by inspirator action of the fuel upon being discharged from the nozzle, the design of the mixing tube and nozzle being such that the fuel is thoroughly mixed with preferably a maximum amount of air 1929. Serial No. 380,000.

without causing back-firing in the tube, before delivery to the combustion chamber. The remaining portion of air r uired to support complete combustion of t e fuel, and termed-the secondary air, is drawn through 65 the air intake passage about the mixing tube, and combined with the premixed charge at the point of combustion, the quantity of the secondary air being adjustable in accordancev with the amount of fuel taken into the burner d and the form of flame desired. By virtue of fuel being thoroughly pre-mixed with a substantial quantity of the re uired amount of total air, upon admixture o this charge with the secondary air at the flame end of the mixing tube, rapid `and complete combustion of the fuel takes place, and as a result the flame is comparativel intense and short, to the advantage mentioned hereinabove.

The above and numerous additional characteristics and advantages of the invention will be discussed more fully and tobest advantage throughout the followin detailed. description of a typical and pre erred embodiment of the invention, reference being had throughout the description to the an nexed drawings, in which:

Fig. l is a diagrammatic and general illustration of the burner positioned in thefwall of a furnace;

7amig. 2 is an enlarged and medial vertical section through the burner;

Fig. 3 is a reduced horizontal medial section on line 33 of Fig. 2;

Fig. l is an end view within the outer casing taken on line 4 4 of Fig. 3; and

Fig. 5 is a fragmentary end section on line 5-5 of Fig. 2 illustrating in detail the shape of the adjusting cam.

In the drawings, numeral indicates a tubular casing, preferably rectangular in section, and adapted to be laced in the furnace wall as illustrated in ig. l, the casing defining a passage 11 through which air is drawn into the combustion chamber C of the furnace. The inner end 10a of the casing opens into the combustion chamber, the outer vend being provided with an adjustable closure 12, hereinafter described in detail, for regulating the flow of air through passage 11.

'lol

A fuel nozzle 13 is mounted within the casing near its intake end, and is su ported by the fuel inlet pipe 14 threaded 1nto the nozzle and commumcating with the supply pipe 15 through the lower wall of the casing. As shown particularl in Fig. 3, a fuel nozzle 13 extends lateral y within the inlet end of the casing and has formed therein a series of spaced openings 16 at its discharge end 13a, through which the fuel is discharged in `the form of a substantially iiat stream. Although the burner may be formed in any suitable manner, it is shown typically herein as comprising-a lower half section 13b intowhich pipe 14 is threaded, and an upper portion 13o secured to the lower section by means of screws 17. Substantially the same delivery or distribution of the fuel in a' flat stream from the discharge end of the nozzle, may be had by forming a continuous slot thereacross instead of the spaced openings 16, the provision of a plurality of spaced orifices however being preferred.

A fuel and air mixing tube 20 extends longitudinally and centrally within the casling 10, the portion 20a of the mixing tube toward its outlet end or mouth 21 being of comparatively elongated or flattened cross section as will be readily apparent from Figs. 2 and 3. The upper and lower sides 2Gb, 20o of the mixing tube diverge as at 22 toward the inlet end, thereby providing a comparatively enlarged interior space within which the fuel nozzle 13 is positioned. Also the sides 20d of the mixing tube preferably diverge toward the inlet end in a similar manner, as shown in Fig. 3. The mixing tube 20 is interiorly supported at op posite sides at its inlet end from the nozzle 13 by means of bolts 24 threaded into the tube and extending through guide openings 25 in the ends of the nozzle, the tube being supported at its opposite end by means of integral ears 27 restino' on lugs 28 projecting from the side walls of'a the casing. The mixing tube may be adjusted longitudinally within the passage 11 by means of nuts 30 threaded on bolts 24 on opposite sides of the nozzle `ends, the lower side 20c of the tubebeing slotted as at 31 to accommodate the longitudinal movement of the tube 2.

If it is desired, a plurality of vertically spaced lugs 28 may be formed on the sides of the casing to enable vertical adjustment of the mixing tube, bolts 24 having suilicient clearance within openings 25 to accommodate pivotal movement of the tube about this point. Also the tube may be slotted in the upper side at its intake, and as at 31a to en able the tube to be inverted within the casing for purposes of directing the flow aswill be mentioned later.

It will be noted that the sides of the nozzle are tapered toward the'fiattened portion 20a of the mixing tube and generally in accordof air in being drawn through the open intake end of the mixing tube. The latter has an integral and downwardly curved lip portion 33 at its discharge end, the under sidel of the tube being cut away as at 34 to form the outlet, and the lip 33 serving as a deflecting means whereby the fuel and vair mixtuge is directed Adownwardly upon being discharged from the mixing tube, the flame as a result being confined to the lower interior of the combustion chamber. Should it be desired, however, to direct the flame upwardly within the combustionchamber, this may readily be done by inverting the mlxing tube as described.

The fuel, upon being discharged through openings 16 at high velocity, serves by inspirator action to draw a certain amount of air, that is the primary air, into the reduced portion of the mixing tube by way of space Y S, the fuel and air thereafter being subjected to intimate and thorough admixture u on passing in turbulent flow rthrough the at- S tened section 20a of the tube. It may be statshape of the mixing-tube an nozzle, and by properly. adjusting the relative positions of the two, proportionng of the fuel and air may be effected in a manner such that a maximum amount of air is mixed with the fuel in passing through tube 20, without causing back-firing through the mouth 21.

The amount of air taken in through passage 11 between the mixing tube and the casing, for admixture with the premixed fuel and air discharged at the mouth of tube 20, is regulated by means of the adjustable closure 12, which is typically and preferably in the form of a door 12 hinged at 36 on the upper end of the casing. A rotatable cani 37 is mounted on the interior side of the door 12, the cam having an integral shank 38 extending through an opening 39 in the door and the shank having an adjustment knob 40 secured to its outer end. Turning of the cam from a given position of adjustment normally 1s prevented by means of a spring 41 placed within an annular recess 42 in the knob and bearing against the outer surface of the door, the inner side 37a of the cani being urged into frictional engagement with the inside of the door to such a degree as to normally prevent its turning. The flanged side 37?) of the cam is adapted to engage the lower curved surface 45 of a boss 46 depending from the upper interior side of the casing. As shown particularly in Fig.` 5, the cam is peripherally shaped generally in the form of a convolute and has gradually increasing radii r, r in a counterclockwise direction about the shank 38. Thus upon turning the knob t() to rotate the cam in an opposite or clockwise direction, the cam by virtue of itsincreasing radius, tends to swing the door out- "Ward about its hinge, for instance as shown in flig. l, free vertical turning engagement Q0 with the boss 46 being facilitated by curving its cam engaging surface at as previously mentioned. Thus by regulating the position of cam 37, the door may be adjusted between closed and full open po-sitions, thereby enabling a sensitive quantity adjustment of the air talren through the passage l1 for final admizture the pre-mixed fuel and air discharged from the mixing tube, and enabling the air intake to be closed when the burner is not in use and when it is desired to retain the heat in the combustion chamber.

Vllhe combined amounts of air taken thIOugIh the mixing tube and passage 11 are of course bastion of the fuel, and possibly somewhat in excess. llt will be noted however that by virtue of a considerable portion of the air having been pre-mixed with the fuel in flowing through the mixing tube, thereby protil riding a mixture combustible to a substantial degree, rapid and complete combustion of the fuel is had at the point of combining the secondary air with the pre-mixed charge. its a result, the flame is comparatively short and intense and does not tend to sweep the combustionchamber to the point of contacting with the heating elements therein, the latter instead being exposed only to the hot gases of combustion.

llt will be understood the drawings and description are to be considered merely as illustrative of and not restrictive on the broader claims appended hereto, for various changes in design, structure and arrange- 555 ment may be made without departing from the spirit and scope of said claims.

l claim l. A burner embodying a tubular casing forming an air passage, a fuel and air mixl ing tube extending longitudinally within the casing, a fuel nozzle in said tube, means for mounting said mixing tube on said nozzle, and a fuel inlet extending through the sides of the casing and mixing tube to the nozzle.`

t5 2. A burner embodying a tubular casing that required to support and complete com` forming an air passage, a fuel and air mixing tube extending longitudinally Within the casing, a fuel nozzle at the inlet end of said tube, the mixing tube being adjustable longitudinally Within the casing relative to the nozzle y and means for supporting one end of said mixing tube on the nozzle.

3. A burner elnbodying a tubular casing forming an air passage. a fuel and air mixing tube extending longitudinally within the casing and spaced therefrom, a fuel nozzle in said tube, means for supporting opposite ends of said mixing Vtube on the nozzle and casing respectively, and means for controlling the flow of air through the spac between said mixing tube and the casing.

4. In a. burner, an air and of {iat-tened cross section, the upper and lower sides of the tube diverging at the inlet end thereof, a fuel nozzle extending laterally within saidv inlet end of the tube, theupper and lower sidesy of the nozzle being tapered toward said flattened portion of the mixing tube, and a fuel inlet pipe extending through the side of said tube and supporting the nozzle, the mixing tube being longitudinally adjustable relative to the nozzle.

5. In a burner, a tubular casing forming an air passage, an air and fuel mixing tube of flattened cross section extending longitudinally within the casing and spaced therefrom, the upper and lower sides of the tube diverging at the inlet end thereof, a fuel nozzle extending laterally Within said inlet end of the mixing tube, a fuel inlet pipe extend through the sides of said tube and supporting the nozzle, the mixing tube being longitudinally adjustable Within the casing, and means for regulating the flow of air through said casing.

6. A burner embodying atube casing forming an air passage, an air inlet for said casing, an open end fuel and air mixing tube extending longitudinally Within the casing, the inlet end of said tube being within said casing and spaced from the inlet end thereof, a fuel nozzle at the inlet end of said tube, 'an adjustable closure for said inlet end of said casing and opposite the end of said mixing tube, and means for adjusting the closure to control the flow of air through said passage.

7. A burner embodying a tubular casing forming an air passage, an open end fuel and air mixing tube extending longitudinally within the casing, the inlet end of said tube being Within said casing and spaced from the inlet end thereof, a fuel nozzle at the inlet end of said tube` a door pivotally mounted on said inlet end of said casing and opposite the end of said mixing tube, and means for pivotally adjusting said door to control the flow of air through said passage.

8. A, burner embodying, a tubular casing forming an air passage, an open end fuel and air mixing tubeextending longitudinally within the casing, the inlet end of said tube fuel mixing tube llil being Within said casing and spaced from the inlet end thereof, a'fuel noz`zle in said tube a. door pivotally mounted on the inlet end o said casing and opposite the end of said mixing tube, and cam means mounted on the door and operable to pivotally adjust the door to control the iow of air through said passage. 9. A burner embodying a. tubular casing forming an air passage, a fuel and air mixing tube extending longitudinally Within the casing, a fuel nozzle at the inlet. end of the tube, means for controlling the flow of air through said passage, a support for the inlet end of said mixing tube, and means vfor adjustably supporting the outlet end of'said mixlng tube at predetermined vertical intervals.

In Witness that I claim the foregoing I have hereunto subscribed my name this 6th day of July, 1929. Y

KENNETH B. ANDERSON. 

